The specific objective of this contract is for the continued maintenance and expansion of the National Research Roster of patients and families affected by Huntington Disease. The Contractor shall collect data on persons with Huntington Disease, persons at risk of the Disease, and people who are related to those with or at risk of the Disease. The Roster will be used to contact potential participants for research studies, to locate individuals of particular research interest, and to provide statistical and demographic data on Huntington Disease. The Roster of patients and families affected by Huntington Disease is expected to continue to be a valuable resource for future research.